recovery from VPS shunt

My husband had a ventriculoperitoneal shunt put in 13 days ago for hydrocephalus.  The hydrocephalus followed a brain hemorrhage which he had a drain, that was later removed, 36 days ago.  The hydrocephalus and VPS shunt was done in a second hosptilization.  He had a cat scan two days ago for positional headaches (OK lying down, headache when sitting up) and his neurosurgeon has said the scan looked good, the ventricles looked good.  As of yesterday, he is experiencing intense vertigo and vomited once.  If he keeps his head absolutely still (not moving from side to side) he can avoid the vertigo/naseau.  He was also on 2 blood pressure medications post op, one of which he discontinued on the advice of his primary care physician after we spoke with the neurosurgeon about this. He is still taking amlodopine every six hours.  His blood pressure readings are in the normal-ish range. My question is:   is the vertigo part of the recovery process, is it possible that he has a shunt leak or flow problem where he just had a cat scan two days ago that showed all was working?  Any information anyone can provide would be appreciated.  Thanks.  Very concerned wife.